Phosphorus induced formation of a NiWO4 phase in the oxide form of P-Ni-W/Al2O3 catalysts

Tailoring Alumina Support with Crystalline AlPO4-5 for Enhancing Hydrodesulfurization Activity

“…It is apparent that there are two peaks at 590 nm and 630 nm, characteristics of tetrahedrally coordinated Ni 2+ ions in NiAl 2 O 4 , in the spectra of NiW/Al 2 O 3 , agreeing well with the previous reports [22,23]. However, with the incorporation of AlPO 4 -5 into alumina, such visible peaks disappear.…”

“…However, with the incorporation of AlPO 4 -5 into alumina, such visible peaks disappear. Moreover, the band around 420 nm, characteristic of octahedrally coordinated Ni 2+ ions, shifts to higher wavenumbers indicating an increased incorporation of nickel with tungsten producing Ni-W-O species [22,23]. Consequently, it is safe to conclude that the tailoring effects of aluminophosphate framework of AlPO 4 -5 on alumina, can, to some extent, impede the diffusion of Ni ions into the alumina lattice [22,23], and facilitate the Ni 2+ ions to be octahedrally coordinated on the composite support AAP.…”

ETS-10 Modulation to Alumina Support and its Promotion for Hydrodesulfurization

“…As the DRS spectra shown in figure 5, two visible peaks at 590 and 630 nm, are found, respectively, ascribed to the presence of tetrahedrally coordinated [14][15][16]. In contrast, no such obvious peaks exist in the spectra of NiW/AETS.…”

“…In contrast, no such obvious peaks exist in the spectra of NiW/AETS. But it can be clearly seen that the band around 420 nm, characteristic of octahedrally coordinated Ni 2+ ions, shifts to higher wavenumbers with the introduction of ETS-10 into alumina, indicating an enhanced incorporation of nickel with tungsten producing Ni-W-O species [15,16]. Therefore, it can be safely concluded that the Ni 2+ ions are liable to be octahedrally coordinated on the composite support AETS due to the modifying effects of titanosilicate framework of ETS-10 on alumina, which effectively impedes the diffusion of Ni ions into the alumina lattice [15,16].…”

Superficial characterization and hydroconversion of tetralin over NiW sulfide catalysts supported on zirconium doped mesoporous silica

“…One that has attracted much attention is phosphorous. The influence of phosphorous concentration on the HDS and hydrogenation activity of tungsten-based catalysts has been studied in a limited number of papers [18][19][20][21][22]. In these NiW catalysts, the incorporation of phosphorous can modify the dispersion of nickel and tungsten in such a way that, depending on the phosphorous concentration and the method of incorporation, the distribution of WO 3 and NiWO 4 phases are different.…”